This invention relates generally to pyrotechnic mixtures and, more particularly, to pyrotechnic mixtures for use in initiator devices having a low firing energy.
Initiator devices or assemblies, such as composed of an initiator transducer and a supply of energetic and rapid burning primer material, have been developed for use in various assemblies. For example, inflatable restraint systems such as used in the protection of vehicle occupants in the event of a collision commonly include or incorporate one or more gas generating or supplying devices each commonly referred to as an xe2x80x9cinflator.xe2x80x9d Inflators used for inflating one or more inflatable airbag cushion or similar inflatable element typically include an initiator device or assembly for igniting a supply of gas generant reactant housed or contained within the inflator housing.
Common primer materials used in such initiator devices or assemblies include lead styphnate and zirconium potassium perchlorate (commonly referred to as xe2x80x9cZPPxe2x80x9d), as well as other pyrotechnic mixtures or formulations. Unfortunately, various of such common or conventional primer materials, while energetic and rapidly burning, are typically difficult to handle in a desirably safe manner. Further, at least some such common or conventional primer materials may require exposure to a higher than desired firing energy in order to effect initiation or reaction thereof.
In addition, where such primer materials are used in or as a part of a gas generating or supplying device, primer materials which, upon reaction, additionally generate, produce or otherwise provide additional gaseous products are generally highly desirable as such additional gaseous products can supplement the gas otherwise provided or supplied thereby. For example, in various inflatable restraint system inflator applications, it may be desirable to employ an initiator device primer pyrotechnic formulation that itself forms gaseous products upon the reaction thereof.
In view of the above, there is a need and a demand for improved pyrotechnic compositions. In particular, there is a need and a demand for a pyrotechnic composition such as may be used as a primer material in initiator devices and such as may provide or result in increased or improved safety in handling, as compared to conventional primer materials. Further, there is a need and a demand for a pyrotechnic composition such as may be used as a primer material in initiator devices and such as may require exposure to a suitably lower or reduced firing energy, as compared to conventional primer materials, in order to effect initiation or reaction thereof. Still further, there is a need and a demand for a pyrotechnic composition such as may be used as a primer material in initiator devices and such as may produce, provide or otherwise desirably result in the formation of additional gaseous reaction products.
A general object of the invention is to provide an improved pyrotechnic composition.
Another general object of the invention is to provide an improved initiator device having a low firing energy.
A more specific objective of the invention is to overcome one or more of the problems described above.
The general object of the invention can be attained, at least in part, through a gas generant pyrotechnic composition which includes a mixture containing:
a fuel component comprising a quantity of at least one Iron Blue Pigment and
an oxidizer component comprising at least one oxidizer effective, upon reaction initiation with at least a portion of the quantity of the at least one Iron Blue Pigment, to produce gaseous reaction products.
The prior art generally fails to provide an initiator pyrotechnic mixture having either or both as low as may be desired firing energy and which facilitates or otherwise more easily permits handling in a desirably safe manner.
The invention further comprehends, in accordance with another preferred embodiment of the invention, an initiator device which includes a charge holder housing containing a gas generant pyrotechnic composition, such as described above, and an initiator transducer in reaction initiating communication with at least a portion of the gas generant pyrotechnic composition contents of the housing.
In accordance with still another preferred embodiment, the invention further comprehends an initiator device which includes a charge holder housing containing a gas generant pyrotechnic composition and an initiator transducer in reaction initiating communication with at least a portion of the gas generant pyrotechnic composition contents of the housing. The gas generant pyrotechnic composition includes:
a fuel component comprising a quantity of at least one Iron Blue Pigment, the gas generant pyrotechnic composition having an Iron Blue Pigment relative content of about 30 to about 50 wt. %,
an oxidizer component comprising potassium perchlorate and effective, upon reaction initiation with at least a portion of the quantity of the at least one Iron Blue Pigment, to produce gaseous reaction products, the gas generant pyrotechnic composition having a potassium perchlorate relative content of about 50 to about 70 wt. %, and
at least about 0.25 wt. % and no more than about 5 wt. % of at least one additive selected from the group consisting of binders, rheology enhancers and wetting agents.
As used herein, references to xe2x80x9cIron Blue Pigmentxe2x80x9d are to be understood to generally refer to that class, family or variety of pigment materials based on microcrystalline Fe(II)Fe(III) cyano complexes. According to results obtained by X-ray and infra-red spectroscopy, the basic general chemical formula for the Iron Blue Pigments is believed to be:
Me(I)Fe(H)Fe(III)(CN)6.H2Oxe2x80x83xe2x80x83(1)
In this formula, Me(I) stands for potassium, sodium or ammonium, with the alkali ion being believed to play a decisive role in the color properties of Iron Blue. Iron Blue Pigments, also sometimes referred to as xe2x80x9ciron ferricyanidesxe2x80x9d have been produced or sold under a variety of different names related to either the place where the compound was made or to represent particular optical properties. Examples of such different names include: xe2x80x9cBerlin Bluexe2x80x9d, xe2x80x9cBronze Bluexe2x80x9d, xe2x80x9cChinese Bluexe2x80x9d, xe2x80x9cMilori Bluexe2x80x9d, xe2x80x9cNon-bronze Bluexe2x80x9d, xe2x80x9cParis Bluexe2x80x9d, xe2x80x9cPrussian Bluexe2x80x9d, xe2x80x9cToning Bluexe2x80x9d and xe2x80x9cTurnbull""s Bluexe2x80x9d, for example.
Other objects and advantages will be apparent to those skilled in the art from the following detailed description taken in conjunction with the appended claims and drawings.